Does IMD forecast signal monsoon acing El Nino in 2019?

NEW DELHI: IMD has forecast a “near normal” monsoon this year while also indicating that a weak El Nino is likely to persist through the rainy season. If both forecasts hold true, it would be only the second time in nearly 50 years that India will have a normal monsoon in an El Nino year.

There have been nine El Nino years since 1970, and only once has the Indian summer monsoon remained unscathed from its influence. That was in 1997, when despite one of the strongest El Ninos, the monsoon ended 2% above normal.

In the other eight instances, the June-September rains in India were hit irrespective of El Nino’s strength — weak, moderate or strong — indicating a strong link between the weather anomaly in the Pacific and monsoon’s performance in India.

El Nino is an abnormal warming of ocean waters in east and central equatorial Pacific that drives changes in wind currents which, in turn, have weather impact around the world.

Apart from 1997, other instances of good monsoons during El Nino years are all from the 1950s and 60s. “There are two years when the monsoon was normal or above normal during a weak El Nino, 1953 and 1969. This year’s El Nino is also predicted to be weak,” said D Sivananda Pai, IMD’s lead monsoon forcaster. The monsoon also defied El Nino in 1957 and 1963, IMD records show.

However, the link between El Nino and poor monsoon appears to have strengthened in recent decades. All four El Ninos since year 2000 have adversely impacted rainfall in India. This includes a weak episode in 2004, which led to a drought year with the monsoon ending at 14% below normal.

In recent years, just a warming in the Pacific, which didn’t result in an El Nino, is believed to have impacted the monsoon in 2012 and 2014. However, every El Nino is unique with its own peculiarities. How it plays out, and whether large-scale features that depress the monsoon actually develop, remains to be seen.